In many injection molding apparatus designs, seals used with nozzles fail during operation or assembly.
Failure can be of several modes. First, the seal may not seal adequately. If the seal is the primary seal, failure will likely result in downtime. Failure can be a result of poor mating between sealing surfaces, overstress and possible breakage of the seal under high molding pressures, or another cause. Second, the seal may become inadvertently disengaged from the nozzle and so become lost or damaged. During assembly or maintenance, loose seal pieces may fall off nozzles or become lodged inside nozzle wells. Third, the seal may not deliver the thermal characteristic expected. For example, the seal may not meet the demanded thermal insulation for the nozzle tip, resulting in the need to quickly replace the seal with another one.
These and other problems can occur together or separately and are best avoided for smooth injection molding operations.